Referring to FIG. 1, there is shown a block diagram of a conventional radio-frequency (RF) emitter. A RF emitter 10, used for emitting RF signals mainly comprises a plurality of amplifying units 111/113, a plurality of input ports 131/151, a plurality of output ports 133/153, and a plurality of passive networks 121/123. In this connection, the passive networks 121/123 are located between the input ports 131/151 and the corresponding output ports 133/153, respectively, while the amplifying units 111/113 are located in the corresponding passive networks 121/123, respectively.
The first passive network 121 comprises a first input passive network 1211 and a second output passive network 1213. In this case, the first input port 131 is connected to the first output port 133 via the first input passive network 1211 and the first output passive network 1213. Between the first input passive network 1211 and the first output passive network 1213, there is provided with a first amplifying unit 111, by which a first RF signal 141 inputted from the first input port 131 is amplified. Subsequently, the amplified first RF signal 141 is then sent to the first output port 133. In the first input passive network 1211 and the first output passive network 1213, a plurality of capacitors and inductors are provided. Moreover, suitable capacitors and inductors are selected cooperatively, such that impedance in the first input passive network 1211 and that in the first output passive network 1213 may meet expectations. For instance, impedance presented in the first input passive network 1211 with respect to the frequency-band of the first RF signal 141 may become low.
The second passive network 1231 comprises a second input passive network 1231 and a second output passive network 1233. In this case, the second input port 151 is connected to the second output port 153 via the second input passive network 1231 and the second output passive network 1233. Between the second input passive network 1231 and the second output passive network 1233, there is provided with a second amplifying unit 113, such that a second RF signal 143 inputted from the second input port 151 may be allowed to pass through the second amplifying unit 113, by which the second RF signal 143 inputted from the second input port 151 is amplified. Subsequently, the amplified second RF signal 143 is then sent to the second output port 153. In the second input passive network 1231 and the second output passive network 1233, a plurality of capacitors and inductors are provided. Moreover, suitable capacitors and inductors are selected cooperatively, such that impedance in the second input passive network 1231 and that in the second output passive network 1233 may meet expectations. For instance, impedance presented in the second input passive network 1231 with respect to the frequency-band of the second RF signal 143 may become low.
Lower impedance may be presented in the first input passive network 1211 and the second input passive network 1231 with respect to RF signals in different frequency-bands, respectively. In practical application, therefore, RF signals may be sent in different input passive networks 1211/1231 selectively on the basis of frequency thereof, so as to enhance efficiency in signals transmission. For instance, the first input passive network 1211 is used as the input passive network for the first RF signal 141, while the second input passive network 1231 is used as the input passive network for the second RF signal 143, in which the frequency-band of the first RF signal 141 is different from that of the second RF signal 143.
When the above RF emitter 10 is provided, RF transceiving in several independent frequency-bands may be provided on one single module, and the highest efficiency of signal transmission may be achieved together with the reduction of harmonic interference occurring in the process of transmission of RF signal by designing the passive network with respect to the RF signals 141/143. The number of passive networks and amplifying units in the RF emitter 10, however, certainly be increased along with more different frequency-bands included in the RF signals to be emitted. In this way, the size and setup cost of RF emitter 10 should be increased.